Field of the Invention
The invention relates to a terpene resin-based aqueous binder, and a method of using the same for preparing an anode for lithium ion batteries or a supercapacitor.
Description of the Related Art
The manufacturing process of a battery or a supercapacitor requires a binder to bond the electrode active material. Conventional organic binders, e. g., polyvinylidene fluoride (PVDF), tend to absorb the electrolyte and swell, thereby reducing the bond performance of the binders, and the volume of active particles often changes during charging and discharging. In addition, PVDF is generally dissolved in N-methyl-2-pyrrolidone (NMP), which is volatile, flammable and explosive, thereby posing serious pollution problems.
Water-based binders are inexpensive and environment friendly, and thus potentially useful for developing binders for lithium ion batteries. For example, carboxymethyl cellulose (CMC)/styrene-butadiene rubber (SBR) is a common water-based binder used in lithium ion batteries. However, when CMC/SBR is used in the graphite anodes, the impedance of the solid electrolyte interface is large, which is unfavorable to the extraction of the lithium ions and adversely affects the long-term cycle performance and high-rate charge-discharge performance of batteries.
Terpene resin, molecular weight of about 650-1200, is made from natural turpentine, has excellent thermal stability, good aging resistance, good compatibility with styrene-isoprene-styrene (SIS), styrene-butadiene-styrene (SBS), ethylene vinyl acetate (EVA) and natural rubber. It can be used in the field of rubber, adhesive, pressure-sensitive adhesive, hot-melt coatings, paints, packing, antirust oil, chewing gum, etc.